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Author Topic: Lets See If I Can Break It (My MDR)  (Read 8958 times)
ES Tactical
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« Reply #100 on: June 01, 2018, 12:05:26 AM »

I can answer that question pretty easily. I'm going to be switching to the factory 6 position valve as they are available. They cover the range of the valve I have been using, plus a little more. Ive had mine choked down pretty good for the 6.5 Creedmoor. Other critical dimensions are the same.

Sent from my SM-G950U using Tapatalk

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CabbitOne
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« Reply #101 on: June 01, 2018, 12:16:01 AM »

I can answer that question pretty easily. I'm going to be switching to the factory 6 position valve as they are available. They cover the range of the valve I have been using, plus a little more. Ive had mine choked down pretty good for the 6.5 Creedmoor. Other critical dimensions are the same.

Sent from my SM-G950U using Tapatalk


Forgive me if this has already been asked of you in another thread. But, could you let us know the dimensional differences between yours and DTís .308 barrels? Not looking, necessarily, for numerical differences, just what is different. (What is your secret sauce?) Also, which parts are factory and which are yíall producing?
Wondering if your barrels would fix some/most of my problems... If so, Iíll order one when DT eventually sends me my rifle back.
« Last Edit: June 04, 2018, 04:19:01 PM by CabbitOne » Logged
Blackandwhiteknight
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« Reply #102 on: June 01, 2018, 12:17:12 AM »

I can answer that question pretty easily. I'm going to be switching to the factory 6 position valve as they are available. They cover the range of the valve I have been using, plus a little more. Ive had mine choked down pretty good for the 6.5 Creedmoor. Other critical dimensions are the same.

Sent from my SM-G950U using Tapatalk



Thanks for responding. Looks like you guys make some great stuff.  There has been quite the discussion about the chamber dwell time in the MDR as it relates to the torn case rims.  Do you feel the gas piston chamber needs more volume to increase the dwell time, or is lowering the port size enough?  Also curious your thoughts on the gas ring setup for the plug.  I see the SCAR doesn't have them but the fit seems much tighter?  I'm getting torn rims when the gun is dirty, but not when it is clean.  I'm getting the feeling that the fouling is sealing the gap around the gas plug rings and upping the pressure. Still have the stock plug. Thanks for supporting the MDR.
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rtp
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« Reply #103 on: June 01, 2018, 12:33:25 AM »

Anyone run steel through there MRS?  Curious if the harder case is still having the same extraction issues.

I've shot Hornady steel match through it without issue, pmc in a few variants, Malaysian 80s surplus ball, Outback 168 SMK, fgmm 175....without issue so far.  PPU Match and IMI Match flat out count shoot more than 1-2 rds without a stuck csee/ripped rim.

As far as heating up causing issues...not sure. I likely did the most rapid fire with the surplus ball ammo without issue, which was AFTER seeing issues with the IMI and PPU. I'm nearly out of my 'random factory ammo' collection I'd picked up for the MDR initial testing, but depending on how the next outing goes with the new gas plug, may look at present and post firing case dimensions vs the PPU and IMI Match to see if anything of interest is seen, e.g. tighter in chamber.
« Last Edit: June 04, 2018, 07:40:31 AM by rtp » Logged
rtp
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« Reply #104 on: June 01, 2018, 12:35:08 AM »

I can answer that question pretty easily. I'm going to be switching to the factory 6 position valve as they are available. They cover the range of the valve I have been using, plus a little more. Ive had mine choked down pretty good for the 6.5 Creedmoor. Other critical dimensions are the same.

Thanks for this.
Can you say if your .308 barrel chambers are cut to your specs or to DT'S?
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Masamuneccc
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« Reply #105 on: June 03, 2018, 10:19:45 PM »

I just got my MDR and all day i was having rounds stuck like in all your pics. Also having a hard time dropping mags out. Upon dissassembling i found there is a lin missing in my mdr for the mag release. Anyone else have this issue?


* 20180603_205759.jpg (2535.7 KB, 4032x3024 - viewed 118 times.)
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JesseJames38
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« Reply #106 on: June 03, 2018, 10:39:14 PM »

Yeah, there are a few people who reported this problem with the pin walking out of the bar to the counter balance.  Seems everyone found there's in the bottom of the receiver.

Just wondering, what kind of ammunition are you using?

Jesse
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Blackandwhiteknight
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« Reply #107 on: June 04, 2018, 11:31:17 AM »

Yeah, there are a few people who reported this problem with the pin walking out of the bar to the counter balance.  Seems everyone found there's in the bottom of the receiver.

Just wondering, what kind of ammunition are you using?

Jesse

See this thread I posted for info.

http://bullpupforum.com/index.php?topic=12968.0
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Masamuneccc
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« Reply #108 on: June 05, 2018, 08:50:53 AM »

@jessejame , i was using pmc bronze .308 win. I never saw the pin at all. As of now the guys at Desert Tech are extreamly helpful.  Love this rifle shoots like a dream.
« Last Edit: June 05, 2018, 08:52:47 AM by Masamuneccc » Logged
wagrn
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« Reply #109 on: June 06, 2018, 02:03:57 PM »

Has anyone tried break in in stages? I was thinking about running the first 50-75 on adverse with the ejection cover off. My thinking was to allow wear on the extractor and trigger group first with one less obstacle then the next 75 with the cover, re evaluate any change then finish the last 50 or so, then try again in normal. Any thoughts o ideas?
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Blackandwhiteknight
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« Reply #110 on: June 06, 2018, 03:27:55 PM »

Has anyone tried break in in stages? I was thinking about running the first 50-75 on adverse with the ejection cover off. My thinking was to allow wear on the extractor and trigger group first with one less obstacle then the next 75 with the cover, re evaluate any change then finish the last 50 or so, then try again in normal. Any thoughts o ideas?

Really shouldn't need to. This is pretty good advice.

http://bullpupforum.com/index.php?topic=13079.0
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CabbitOne
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« Reply #111 on: June 07, 2018, 11:45:48 AM »

Emailed DT at 0800 today (06/07/18), looking for some kind of update. It has now been three weeks that they've had my rifle. Far longer than I have had it.

For anyone just now joining this topic, I highly recommend you read what has transpired thus far in the first post and subsequent range report. TLDR version; the rifle has already been back to DT once and still isn't working. Also shipping error. Rifle completed 220 rounds and is no closer to being functional.

Also, feel like I should change the name of the thread... considering I didn't have to do anything to break the rifle.... Maybe, "Lets See If I Can Fix It (My MDR)" ?
« Last Edit: June 07, 2018, 11:52:51 AM by CabbitOne » Logged
thehun
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« Reply #112 on: June 07, 2018, 12:31:17 PM »

Maybe maybe...yours is the guinea pig for a worthy update.
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CabbitOne
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« Reply #113 on: June 08, 2018, 05:27:48 PM »

Received a response yesterday (06/07/16);

Quote from: DT Warranty Service
Yes, I have addressed almost all the issues with your rifle. It runs great on the XM80 from American Eagle, I also have tried many others; Hornady match, PPU match, PPUxm80, and PMC Bronze. As far as ammo is concerned, I would stick to the better ones, it really liked the AE XM80, and PMC Bronze. I would avoid CBC, ZQi, and the like, not only have I heard of poor performance from customers, but I have seen it here as well. The gun runs fine on Normal, I have attached a video link so you can see for yourself:  *snip*

No word on what was actually done to the rifle, though I'm still emailing back and forth. Just sent an email today (06/08/16) asking when I might receive the rifle back.
I will say, in spite of all the trouble I've had with the rifle. I'm happy with DT's customer service. If I'd had these sort of issues and their CS was horrible.... well I don't even want to imagine it.

Also, I asked about the 6 position gas regulator in relation to my specific rifle. The general consensus is it would not improve current performance. I guess I'll see what happens when I get the rifle back and (assuming it works) start trying other loads and suppression.
« Last Edit: June 08, 2018, 05:33:35 PM by CabbitOne » Logged
kfeltenberger
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« Reply #114 on: June 08, 2018, 06:29:20 PM »

Received a response yesterday (06/07/16);

Quote from: DT Warranty Service
Yes, I have addressed almost all the issues with your rifle. It runs great on the XM80 from American Eagle, I also have tried many others; Hornady match, PPU match, PPUxm80, and PMC Bronze. As far as ammo is concerned, I would stick to the better ones, it really liked the AE XM80, and PMC Bronze. I would avoid CBC, ZQi, and the like, not only have I heard of poor performance from customers, but I have seen it here as well. The gun runs fine on Normal, I have attached a video link so you can see for yourself:  *snip*

No word on what was actually done to the rifle, though I'm still emailing back and forth. Just sent an email today (06/08/16) asking when I might receive the rifle back.
I will say, in spite of all the trouble I've had with the rifle. I'm happy with DT's customer service. If I'd had these sort of issues and their CS was horrible.... well I don't even want to imagine it.

Also, I asked about the 6 position gas regulator in relation to my specific rifle. The general consensus is it would not improve current performance. I guess I'll see what happens when I get the rifle back and (assuming it works) start trying other loads and suppression.

I want to know more specifics other than "I've heard..." anecdotes on why it won't work with ZQi M80...given that it is NATO certified and to NATO spec.  Unless the rifle really won't work with 7.62x51 and needs a commercial grade .308 loading... If so, this will be extremely disappointing and a failure on DT's part.
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Kurt
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« Reply #115 on: June 08, 2018, 07:59:30 PM »

Received a response yesterday (06/07/16);

Quote from: DT Warranty Service
Yes, I have addressed almost all the issues with your rifle. It runs great on the XM80 from American Eagle, I also have tried many others; Hornady match, PPU match, PPUxm80, and PMC Bronze. As far as ammo is concerned, I would stick to the better ones, it really liked the AE XM80, and PMC Bronze. I would avoid CBC, ZQi, and the like, not only have I heard of poor performance from customers, but I have seen it here as well. The gun runs fine on Normal, I have attached a video link so you can see for yourself:  *snip*

No word on what was actually done to the rifle, though I'm still emailing back and forth. Just sent an email today (06/08/16) asking when I might receive the rifle back.
I will say, in spite of all the trouble I've had with the rifle. I'm happy with DT's customer service. If I'd had these sort of issues and their CS was horrible.... well I don't even want to imagine it.

Also, I asked about the 6 position gas regulator in relation to my specific rifle. The general consensus is it would not improve current performance. I guess I'll see what happens when I get the rifle back and (assuming it works) start trying other loads and suppression.

I want to know more specifics other than "I've heard..." anecdotes on why it won't work with ZQi M80...given that it is NATO certified and to NATO spec.  Unless the rifle really won't work with 7.62x51 and needs a commercial grade .308 loading... If so, this will be extremely disappointing and a failure on DT's part.

I'll preface this by saying I don't regularly shoot 7.62 or .308, nor am I a reloader.

Wondering if as kfeltenberger pondered that the system is designed for .308 specifically. And/or the chamber is perhaps spec'd to .308 and is at the extreme end of the tolerance, not giving it the extra "give" to accommodate many different loadings. Perhaps this could contribute to the success people have reported with the ES Tactical barrels?

Heck, if the chamber is pushing one direction .308 or 7.62 and is at the extreme end and the gas system was for the other and the extreme end of that, it could be compounding the issue.

That is not even taking into account parts that may be out of spec or whose spec may have been too loose to begin win.

Couple all of this with, none of us know which loads the system was ever tested with and/or designed for.

As far as the ZQI stuff goes, I was of the understanding it was NATO spec as well. But again, I don't shoot .308/7.62 regularly. Nor have I ever purchased ZQI.

I'm very curious/excited to get my rifle back. I badly want it to work, to the point I'm ready to get a ES Tactical barrel if it fixes any issues I may still be having. Heck, I intend on getting one so long as the rest of the rifle is working...
« Last Edit: June 08, 2018, 08:08:18 PM by CabbitOne » Logged
thehun
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« Reply #116 on: June 09, 2018, 12:04:37 AM »

So you would waste $850 bucks on top of $2500 lemon instead of demanding DT to give you a working rifle that you paid for?...its your money but to me that senseless.

If your MDR does not perform after you receive it from DT's warranty service...I would keep sending it back...I would keep sending it back until A) your rifle performs or B) they buy it back and you move on. No platform is worth an extra $850 bucks on a potential fix just to see if it would work.

I keep saying that the MDR is built around their match ammo (but I think there are other issues other than the chamber and gas tuning)...why don't you instead of spending $850 bucks on something that is not really proven either...gamble on DT Match Ammo...say $175 worth...if it functions flawlessly...there is your answer...if it doesn't...well that just sucks even more that the MDR would choke on their very own ammo.


« Last Edit: June 09, 2018, 12:12:39 AM by thehun » Logged
CabbitOne
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« Reply #117 on: June 09, 2018, 01:15:48 AM »

So you would waste $850 bucks on top of $2500 lemon instead of demanding DT to give you a working rifle that you paid for?...its your money but to me that senseless.

If your MDR does not perform after you receive it from DT's warranty service...I would keep sending it back...I would keep sending it back until A) your rifle performs or B) they buy it back and you move on. No platform is worth an extra $850 bucks on a potential fix just to see if it would work.

I keep saying that the MDR is built around their match ammo (but I think there are other issues other than the chamber and gas tuning)...why don't you instead of spending $850 bucks on something that is not really proven either...gamble on DT Match Ammo...say $175 worth...if it functions flawlessly...there is your answer...if it doesn't...well that just sucks even more that the MDR would choke on their very own ammo.




I intend on continuing to send it back until itís working correctly. I was more thinking if the new barrel would fix my (hopefully nonexistent) problems itís a boon. Itís giving me a more useful caliber and allowing me to actually use the thing between trips back to its homeland.

I agree though, DT should make the situation right.

While Iíd be interested to see if the rifle would work with their ammo, doesnít really matter one way or the other. Thatís about as useful to me as saying it works with a laser boresight (sarcasm). Iíd really be curious to know what differences their match ammo might possess compared to other major manufacturerís match ammo. Especially if like you postulate, the MDR is built for that fuel and might prove a salve for these lemony rifles.
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mityno1
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« Reply #118 on: June 09, 2018, 01:42:28 AM »

Differences in ammo:

The powder charge being loaded light or hot and the projectile weight will make a difference in how any semi-auto runs.

Overall cartridge length and projectile ogive (shape of the bullet's nose cone) are two primary differences that could make a big difference dealing with unforgiving feed ramps from one brand of ammo or handload recipe to the next.  

The hardness or softness of the brass shell casing could make a big difference in an unforgiving chamber from one brand of brass to the next.

Basic gunsmithing options to consider:

Reaming the chamber to 7.62x51 (or whatever) might help with a tight chamber but will do nothing for a loose chamber.

Blueprinting and polishing the feed ramps will help any semi-auto feed more reliably. Polishing the feed ramps too much and causing them to go out of tolerance will do the opposite.

« Last Edit: June 09, 2018, 01:44:00 AM by mityno1 » Logged

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thehun
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« Reply #119 on: June 09, 2018, 09:50:58 AM »

So you would waste $850 bucks on top of $2500 lemon instead of demanding DT to give you a working rifle that you paid for?...its your money but to me that senseless.

If your MDR does not perform after you receive it from DT's warranty service...I would keep sending it back...I would keep sending it back until A) your rifle performs or B) they buy it back and you move on. No platform is worth an extra $850 bucks on a potential fix just to see if it would work.

I keep saying that the MDR is built around their match ammo (but I think there are other issues other than the chamber and gas tuning)...why don't you instead of spending $850 bucks on something that is not really proven either...gamble on DT Match Ammo...say $175 worth...if it functions flawlessly...there is your answer...if it doesn't...well that just sucks even more that the MDR would choke on their very own ammo.




I intend on continuing to send it back until itís working correctly. I was more thinking if the new barrel would fix my (hopefully nonexistent) problems itís a boon. Itís giving me a more useful caliber and allowing me to actually use the thing between trips back to its homeland.

I agree though, DT should make the situation right.

While Iíd be interested to see if the rifle would work with their ammo, doesnít really matter one way or the other. Thatís about as useful to me as saying it works with a laser boresight (sarcasm). Iíd really be curious to know what differences their match ammo might possess compared to other major manufacturerís match ammo. Especially if like you postulate, the MDR is built for that fuel and might prove a salve for these lemony rifles.

I think there are some other tolerance issues that are causing problems in the MDR not just the chamber and gas...but since some owners like to experiment...they should start and see how their MDR runs on DT's ammo...$29/20rd is not cheap...but at this point spending $150 to try and see if it chokes would almost be worth it...plus...if it does not run with DT's ammo...I think you have a much better case to DT that your rifle is screwy.

When you have a private label match ammo, like what DT has, its specs can vary from commercial rounds...so if the chamber is spec'd form that round...it might cause issues on others...its just hypothesis that I do not think it has been tried.
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